Beginning this week, the utility is mailing out report card-like audits of energy usage to 130,000 households across Upstate, showing in dollars and cents how their utility bills compare with neighboring households of similar size.

Utility officials say they expect the information to motivate residents to conserve.

The new reports are a “behavior modification” experiment approved in November by the state Public Service Commission, which authorized a similar project for Central Hudson Gas & Electric, a utility in the Hudson Valley.

Some 58,000 households in Central New York — slightly more than 10 percent of the region’s 547,000 households — will receive the “home energy reports” from now until December 2012, said Tom Baron, project manager at National Grid.

If the pilot project succeeds in reducing energy usage, it may be expanded after that, Baron said.

The reports, which are sent independent of monthly bills, compare each recipient’s energy usage to the average usage of 100 similar homes in the area. Residents can see how their electric and natural gas consumption compares with similar homes — and how much money they are saving or wasting as a result.

The report also compares a resident’s usage to the 20 most efficient households in the comparison group. And each report contains several suggestions for how to save energy.

National Grid has 425,000 customers in a similar program in Massachusetts. A third-party audit is under way to document whether the effort produced significant energy savings, but Baron said he is confident the program is successful.

“We have some evidence that there are reductions in both gas and electric usage,” Baron said.

National Grid has contracted with Opower, Inc., of Arlington, Va., to produce the reports.

The PSC authorized Grid to spend $2.6 million on the program. The money comes out of the system benefit charge that customers pay on their utility bills.

National Grid’s goal for the program is to reduce usage by 24.3 million kilowatt-hours of electricity and 1.9 million therms of gas by December 2012. At today’s residential prices, that’s more than $5.3 million worth of energy.